The present invention relates to a multitrack recording apparatus for accurately searching a desired position of a recording medium such as a magnetic tape at high speed.
Tape recorders have been very popular as conventional apparatuses for recording speech, music, and other data. Conventional tape recorders can be classified as cassette or open-reel tape recorders. In either type, a tape counter for indicating the travel length of the tape, or a time indicator for indicating the travel time of the tape, is selectively provided as means for detecting the current tape position in the recording or reproduction mode. However, when one is searching for a given tape position, the tape counter or the time indicator cannot give accurate position information due to elongation and slippage of the tape.
In order to achieve an extremely accurate search for a desired tape position as required by miltitrack recording or cueing at a broadcast station, in accordance with one conventional technique a pulse signal (e.g., if the number of beats per is 200 and the pulse period is 1/96 of a quarter note, the signal frequency is 320 Hz) of a regular period is recorded on one channel of the tape. The pulses of this signal are counted to search the current tape position. According to another conventional tape position detection technique, the time elapsed from the beginning of the music or data is recorded in a specific channel for every predetermined time interval. According to these methods, accurate position detection can be performed compared to detection using a tape counter or time indicator. The technique using the pulse signal, however, imposes limitations on the recording or reproduction frequency (about 20 kHz). The maximum frequency of the pulse signal is limited, and the pulse signal cannot be accurately detected due to tape loosening during starting and stopping of the tape, The tape position detection precision, therefore, cannot be satisfactory.
Conventional multitrack musical recording will be exemplified below. Sync clock signals and click tones must be recorded on both end channels prior to musical recording. Tones from a rhythm sound source (e.g., a drum or bass) are recorded on another channel on the basis of the clock signals and the click tones. Tones from an ensemble sound source (e.g., brass and strings) are recorded on still another channel. In this case, assume that recording is started from an intermediate position. According to a conventional time counting technique, the time between the start position to the intermediate position is checked in advance. The tape is fast forwarded to near the desired position by using a stop watch or the clock signal prerecorded on one channel. When the tape comes near the desired position, it is driven at the normal speed. An operator then monitors the tape with headphones and searches for the desired position. This operation is cumbersome and time-consuming. In addition, since all musical measures do not have an identical period of time, the time data does not always provide accurate position detection.
When a musical piece created by a music sequencer or computer is to be recorded in synchronism with music prerecorded on a tape from the beginning, the clock signal recorded on the tape is used to achieve easy synchronization. However, synchronous recording of the musical piece from an intermediate portion of music already recorded on a tape is very difficult as described above. Moreover, it is impossible to control external music generating equipment, such as a music sequencer and computer, from a tape recorder for the same reason as described above.